This is a report of a follow up study of 26 bypass operations on 14 patients done since April of 1978. Eleven patients showed improved neurological status after operation. Decreased Moyamoya mass and the incresaed size of the superficial temporal artery were shown angiographically with the lapse of time. Good filling of the middle cerebral artery was also demonstrated 10 to 12 months postoperatively. It may be supposed that the bypass surgery in the early stage of Moyamoya disease will produce a good result.
